1. Field
Embodiments of the present invention generally relate to the field of geo-location. More specifically, embodiments of the present invention refer to a method and system for position estimation in geo-location applications.
2. Background
Geo-location refers to an identification of real-world geographic location of a mobile device. Geo-location data can include navigational information such as country, region, city, latitude, and longitude. With the geo-location data, the location of the mobile device can be determined.
One system that provides navigational information for geo-location is a Global Positioning System (GPS), which is a space-based global navigation satellite system. The GPS includes three primary components: a constellation of satellites that orbit the Earth; control and monitoring stations on Earth; and a GPS receiver. GPS satellites broadcast signals from space to the GPS receiver to provide both three-dimensional location (e.g., latitude, longitude, and altitude) and time.
Since its inception, GPS signals have become widely used in many geo-location applications. For instance, GPS signals are used in many transportation systems, ranging from aviation systems to maritime operations. One limitation with current GPS-based geo-location systems, even high-end systems that have an open-air accuracy to within 1 meter, relates to multi-path errors in GPS signals due to obstructions, such as tall buildings and canyon walls, between GPS satellites and GPS receivers. The obstructions can occlude, as well as reflect, the GPS signals, thus causing delays and inaccuracies in navigational information provided by the GPS signals. This limitation of GPS-based geo-location systems is also known as the “urban canyon” issue.
Methods and systems are needed for accurate position estimation in GPS-based geo-location applications.